Thermometer



May 7, 1935. H, Y. NORWOOD 2,000,092

THERMOMETER Filed Oct. l2, 1933 INVENTOR Harry IKNoru/aoa" A). ATTORNPatented May 7, 1935 OFFICE. 1

THERMOMETER I Harry Y. Norwood Rochester, N. Y.', assignor to TaylorInstrument N. Y., a corporation of Application October 12,

1 Claim.

This invention relates to thermometers and more particularly tothermometers of the metallic type.

While bimetallic thermostatic strips have been widely used inthermometers and while these strips have been wound into coils, theyhave either been of cumbersome size or else have failed, in the absenceof gear mechanism, to provide'sufiicient movement to actuate the indexof the thermometer through the desired range.

In accordance with the present invention, it is proposed to provide anindicating thermometer which not only generates a substantial amount ofpower, but which also develops a considerable movement in the actuatingelement for operating the thermometer pointer or other indicator.

Another feature of the invention relates to the provision of athermometer in which the actuating element is relatively inexpensive tomanufacture and yet develops suflicient power and movement for an indexof a thermometer as large as several feet across.

These and other features of the invention will appear from the detaileddescription and claim when taken with the drawing hi which Fig. 1 is afragmentary front view of one form of the thermometer of this invention;Fig. 2 is a side elevation thereof; Fig. 3 is a cross-sectional viewtaken on the line 33 of Fig. 1; Fig. 4 is a cross-sectional view takenon the line 44 of Fig. 3; and Figs. 5 and 6 are respectively a top viewand a front view of a modified form of the invention in which a drumtype indicator is substituted for the index or pointer shown in Fig. l.

Referring to Figs. 1 and 2, 5 designates a circular case in which theactuating mechanism of the thermometer is mounted. The front of thiscase is closed by glass window 6 which protects the index I and thegraduated dial ,8 over which the index moves in response to temperaturechanges; The index is mounted on a shaft 9 extending through the dialand journaled in the frame of the instrument in the manner illustratedin Fig. 3, which frame comprises a fiat strip I0 and a U-shaped piece I!having its ends joined to this strip. The shaft 9 is rotated by acomposite spring formed of a series of helically wound bimetalic coilspring sections I2, I3, I4 and I5 arranged in parallel planes at rightangles to and enclosing said shaft. Of these spring sections, section I2has its end I6 attached in a notch in collar H which is screwed to thestrip New York U V 1933, SerialNo. 693,263

Companies, Rochester,

I6, while a portion of the coil section I2 near its outer or free end isjoined by a rigid connection to an adjacent portion of the outer end ofthe section I3. This rigid connection comprises afiat piece I8 withupset ends engaging re- I 3 and the opposite I V which inclined sidesengage the opposing edges of the mentioned convolutions to force themrespectively toward the adjacent upset ends of piece I8. The inner endof section I3, as indicated at 2i, is attached to the sleeve 22 in anotch therein. This sleeve is freely rotatable on the shaft 9 and hasattached thereto the inner end of the section I4 as indicated at 23. Aportion of section I4 near its free end is connected by a rigidconnection, such as previously described, to a portion of the section I5near its outer end, while the inner end of the section I5 is attached asindicated at '26 to sleeve 2! which is fastened to the shaft 21 by a pin28.

In the operation of the device let it be assumed that the temperaturecondition to which the actuating mechanism is exposed, rises, in whichcase coil sections I2, I3, I4 and I5 tend to unwind. Since one end ofthe coil section I2 is attached to the fixed collar ll, when thissection unwinds it tends to rotate the section I3 which is connectedtoit by the rigid connection including piece I8. Since section I 3 isalso exposed to the rising temperature condition it will likewise tendto unwind and thereby rotate the sleeve 2i to which its inner. end isconnected and as this sleeve rotates on shaft 23, it carries with it thesection I4. This section, since it is likewise exposed tothe risingtemperature, will tend to unwind in like manner and through the rigidconnection 24, will carry with it the outer end of the section I5.Section I5, since it is also exposed to the changing temperaturecondition, will also unwind tate the sleeve 21 and the shaft 9 connectedto it, to swing the index I in a clockwise direction with respect to thedial 8. Thus the motion of one coil is transmitted to the next coil inthe series which, in turn, adds its own movement to that of thepreceding coil, and this action is repeated for each of the succeedingcoils of the series, that is, the expansion of all of the coils of theseries is cumulative. In this manner a wide range of move! and willroment of the actuating mechanism is possible without sacrificing power.

It will be understood that when the temperature condition drops, theactuating mechanism including the composite spring comprising thebimetallic coil sections I2, l3, l4 and 15, functions to swing the index1 in a counterclockwise direction with respect to its dial 8.

In the modified form of the invention illustrated in Figs. 5 and 6, thecase 3flis of generally rectangular form and is provided in its frontface with a window 3!. The actuating mechanism of this thermometer issubstantially the same' as that previously disclosed except the framethereof is changed slightly to adapt it to case 30. In this device,however, the composite spring the coil sections l2,

including [3, l4 and I5 actuates the shaft 23 in the manner already setforth to rotate agraduated drum 32 behind the window 3| and the fixedpointer 33, which is preferably formed as a part of the frame of thewindow.

I claim:

Actuating mechanism for a thermo-responsive device comprising acomposite spring formed of 'coaxially arranged bimetallic coil springsections joined together in series by rigid connections including atleast one sleeve, a collar, one end of said spring being fixed,

other end of said spring,

a shaft attached to the said shaft being rotatable

